Editing Canvas (section)

==As a compound agent==
[[File:Canvas bags.jpg|thumb|[[Canada Post]] canvas bags]]
[[File:Canvas-stretching.jpg|thumb|Stretching canvas on a canoe]]
From the 13th century onwards, canvas was used as a covering layer on [[pavise]] shields. The canvas was applied to the wooden surface of the pavise, covered with multiple layers of [[gesso]] and often richly painted in [[tempera]] technique. Finally, the surface was sealed with a transparent varnish. While the gessoed canvas was a perfect painting surface, the primary purpose of the canvas application may have been the strengthening of the wooden shield corpus in a manner similar to modern [[glass-reinforced plastic]].